The Evolution of Microstructure and Mechanical Properties of Al-Mn-Fe-Si Alloys During Isothermal Annealing
Abstract
Recrystallization during isothermal annealing is studied in a twin-roll cast Al-Mn-Fe-Si alloy with Zr addition. Al3Zr precipitates, which are known to improve the recrystallization resistance by exerting the Zener drag on migrating grain boundaries, form during heat treatment at 450 degrees C.
Materials with and without Al3Zr precipitates are subjected to 4 passes of equal channel angular pressing at room temperature and a submicrometric grain size is achieved. In the course of isothermal annealing materials recrystallize at 400 degrees C, 425 degrees C and 450 degrees C.
The time required for recrystallization follows an Arrhenius equation. Recrystallization kinetics is similar independently of the presence of Al3Zr precipitates.
Precipitation of alpha-Al(Mn, Fe) Si particles is thought to increase the recrystallization resistance in the material without Al3Zr.